Disk drives using various kinds of disks, such as optical disks, magneto-optical disks, flexible magnetic-recording disks, and similar data-storage disks are known in the art. In particular, hard disk drives (HDDs) have been widely used as indispensable data-storage devices for contemporary computer systems. Moreover, HDDs have found widespread application to moving image recording and reproducing apparatuses, car navigation systems, cellular phones, and similar devices, in addition to the computers, due to the outstanding data-storage characteristics of HDDs.
A magnetic-recording disk used in a HDD includes multiple concentric data tracks and servo tracks. A servo track includes multiple servo data regions containing address information. A data track includes multiple data sectors containing user data. A data sector is recorded between separate servo data regions in the circumferential direction of the magnetic-recording disk. A read element and a write element of a head-slider supported by a rotary actuator accesses designated data sectors according to address information in servo data to write data to, and read data from, data sectors.
In order to increase the recording density of a magnetic-recording disk, the clearance between a read/write element of the head-slider flying in proximity to a recording surface of the magnetic-recording disk, and the magnetic-recording disk, as well as variations in the clearance, has continually been decreased, as HDD technology has advanced in concert with the demands of the marketplace for greater recording density. As used herein, the combination of a read element and a write element may be referred to by the term of art, “read/write element.” To this end, some mechanisms have been proposed to control the clearance. One such mechanism includes a heater in a head-slider; the heater heats the read element and the write element of the read/write element and the surroundings to adjust the clearance, which is referred to herein by the term of art, “thermal fly-height control,” or “TFC.” TFC generates heat by applying electrical current to the heater to cause the read element and the write element of the read/write element to protrude by thermal expansion. This reduces the clearance between the magnetic-recording disk and the read/write element, including the read element and the write element. Engineers and scientists engaged in HDD manufacturing and development are interested in the design of HDDs that control the clearance and variations in the clearance between the read/write element of the head-slider and the magnetic-recording disk to meet the rising demands of the marketplace for increased data-storage capacity, performance, and reliability.